To paywall or not to paywall: it's a question that plagues the media. At its heart is a debate about whether your readers are your customers – or your product, to be sold to advertisers.

At Die Tageszeitung, a newspaper based in Berlin, they look at it differently. Its readers are its owners. Quite literally, in fact. Taz – as the paper is nicknamed – is owned by a co-operative of 12,000 readers.

Taz was founded in 1979 by west Germans disenfranchised by the conservative mainstream media and it is a leftwing paper. Half of its readers vote Green. In 2009, on the outside of its office, its journalists unveiled a huge mural of a naked Kai Diekmann – editor of Bild, a rightwing daily. Diekmann's erect penis stretches across all five storeys. The subtext is clear.

For years, Taz – circulation 60,000 – was funded by state handouts. But with the fall of the Wall in 1989 came a drop in subsidy – and by 1992, the paper faced bankruptcy. Enter the Genossenschaft, or co-operative: a group of concerned readers who valued the paper's independence, or its ability, as one has it, "to put its finger into the wounds of our economic system". The group invested its savings in the paper, and the paper was itself saved.

Two decades on, the co-operative's coffers contain €11m (£8.7m). Murdoch, this isn't: anyone can invest as little as €500, and everyone gets an equal say, regardless of their stake. They can't influence the paper's day-to-day operations, but they can propose policy at the AGM. Recent meetings discussed whether to raise freelance fees (yes) and to ban advertising for nuclear energy (no).

The egalitarian approach extends to the 140-strong newsroom. "You're a very free journalist here," says deputy editor Reiner Metzger. Reporters are free to follow their own hobbyhorses, which he says makes life tough as an editor. "People argue very hard. We don't have a hierarchical structure where someone can say: shut up now." Salaries are pretty flat, too. Metzger is paid only €500 more than the most junior reporter – though he gets additional support for his children.

And what about paywalls? Unlikely, he laughs: "We were founded on the idea of distributing information as far as possible."